title: Comparison of IMRT techniques in the radiotherapeutic management of head and neck cancer: is tomotherapy "better" than step-and-shoot IMRT?
abstract: Currently, the most common method of delivering intensity-modulated radiotherapy (IMRT) is through step-and-shoot, segmental multi-leaf collimator (SMLC)-based techniques. Although rotational delivery methods such as helical tomotherapy (HT) have been proposed as offering advantages in the treatment of head and neck cancer, a lack of clinical data exists on its potential utility. This study compared dosimetric, clinical, and quality-of-life endpoints among 149 patients treated by HT and SMLC-IMRT for head and neck cancer. Dosimetric analysis revealed that the use of HT resulted in significant improvements with respect to mean dose (23.5 versus 27.9 Gy, p = 0.03) and V30 (30.1 versus 43.9 Gy, p = 0.01) to the contralateral (spared) parotid gland. However, the incidence of grade 3+ xerostomia in the late setting was 10% and 8% among patients treated by HT and SMLC-IMRT, respectively (p = 0.46). There were no significant differences in any of the quality of life endpoints among patients treated by HT and SMLC-IMRT (p > 0.05, for all). Acknowledging the biases inherent in this retrospective analysis, we found that the dosimetric advantages observed with HT compared to SMLC-IMRT failed to translate into significant improvements in clinical outcome. Prospective studies are needed to further evaluate how HT may affect the therapeutic ratio.
authors.affiliation: Department of Radiation Oncology, University of California Davis Cancer Center, 4501 X Street, Suite G140 Sacramento, CA, USA. allen.chen@ucdmc.ucdavis.edu
authors.forename: A M
authors.initials: AM
authors.lastname: Chen
authors.forename: J
authors.initials: J
authors.lastname: Marsano
authors.forename: J
authors.initials: J
authors.lastname: Perks
authors.forename: G
authors.initials: G
authors.lastname: Farwell
authors.forename: Q
authors.initials: Q
authors.lastname: Luu
authors.forename: P J
authors.initials: PJ
authors.lastname: Donald
authors.forename: J A
authors.initials: JA
authors.lastname: Purdy
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000532:radiotherapy*; D003680:Deglutition Disorders / Q000209:etiology; D018572:Disease-Free Survival; D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D011832:Radiation Injuries / Q000209:etiology; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D036542:Tomography, Spiral Computed / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult